Management at Farmer’s Level to Reduce the Risk of Shrimp Disease Outbreak in Different Farming Systems

Abstract

This present study was conducted to investigate the existing status of management systems of shrimp culture at farmer’s level and to find out any effective system that reduces disease outbreak in shrimp production. Proper management system in aquaculture particularly in shrimp aquaculture is not only important to increase the capacity of per unit production but also to reduce the frequency of disease outbreak which is now a major concern for sustainability of the shrimp sector. Extensive shrimp farming system is mostly practiced in Bangladesh, but in the recent time farmers shows their interest in improved or semi-intensive farming systems as high mortality of shrimp is becoming very frequent in extensive farming system. Effective management system of shrimp farming depends on a variety of factors that include age, education and farming experiences of the farmers, availability of critical inputs, credit facilities, occurrence of natural calamities, socio-political state etc. Both extensive and semi-intensive farmers were interviewed to pick up the differences in farm management systems as well as to find out the probable reasons and driving forces those lead to occurrence of shrimp disease and ultimate lose in shrimp aquaculture. It was found that, in the study area, most of the shrimp farmers were found to be quite middle aged with a range from 17 to 73 and 100% of the interviewee were male. Among the 100 interviewees, 22 respondents were found who had never attended to the school, 52 had completed their primary level. Average size of the farms were found 88.77 decimal in the Semi-intensive sector whereas it was 221.1 decimal for extensive farms. Though the pre-stocking and post stoking management were followed by the both traditional and semi-intensive farmers, the qualitative and quantitative nature of management systems in semi-intensive farms were found quite systematic, regular and scientific. In the study area, semi-intensive culture of shrimp was done for 110-120 days. In both traditional and semi-intensive culture systems, farmers stocked fry from the month of January to August every year and cycle of a culture period extends from 110 to 140 days. The stocking density was found 2-3 PL per m² in traditional system and is 15 PL per m² in semi-intensive systems. In both systems sources of PL were mainly hatchery produced seeds. Though most of the extensive farmers did not use any supplementary feeds in their farms, in semi-intensive systems cost of feed for per acre went up to BDT 215,000. In semi-intensive system during the culture period different types chemicals and additives like Super PS, Super biotic, Mutagen, Zymatin, pH fixer, Biotrim, Soda mix, K-max, Calmag, Sea max, a-soil and dolomite were applied, but no supplementary drugs and additives were applied in traditional culture ponds. The concept of bio-security was found to be followed very strictly in the semi-intensive farms while this concept was not well known to the traditional farmers. Finally, the semi-intensive farmers did not record any disease outbreak in the last three years while the traditional farmers recorded high mortality of shrimp up to four cycles in the last three years. Besides, net return from per unit land use was found more than twelve times higher in semi-intensive system compare to extensive one. Thus, this study revealed the effectiveness of semi-intensive farming system in the reduction of disease outbreak frequencies as well as net return size in shrimp aquaculture. However, further intensive study is needed to justify the present findings properly.